There is at least one coyote living on Martha’s Vineyard. Gus Ben David is 100 per cent sure of that, although he has only 97 per cent proof.

The coyote, or coyotes, have established territory on the north side of the Island, in an area covering part of Chilmark and West Tisbury.

Mr. Ben David, owner of the World of Reptiles and Birds Park, former director of Mass Audubon’s Felix Neck Wildlife Sanctuary and conduit for almost every report of unusual wildlife on the Island, had been growing increasingly concerned over the past couple of years that a coyote was out there. But he became certain only this week.

That was when he got the results of the DNA testing of some scat — that is fecal matter — that had been collected by some concerned north shore property owners and sent, at considerable cost, to a laboratory in California.

“The DNA report came back that it was 97 per cent indicative, consistent with coyote DNA,” Mr. Ben David said.

And that is a big potential problem for Vineyard wildlife, pet and livestock owners. But only a potential problem at this stage, for while the evidence is enough to convince him there is a coyote, there is no evidence yet of more than one.

Mr. Ben David said there had been “scuttlebutt” about coyotes on the Island for years, but until relatively recently, he had dismissed it. No one had ever produced a photograph, much less a specimen.

His views began to change, though, some time before the DNA results.

“In the past two years and particularly within the past year, especially during deer season, we’ve had a lot more reports,” he said.

What’s more, they came from people he considered absolutely reliable.

“They weren’t average Joes,” he said. “They were individuals of the highest integrity and experience. Woodsmen, hunters.

“You accept or don’t accept someone’s sighting depending on their record, you know? It’s like if Vern Laux, Matt Pelikan, Allan Keith, called and said ‘I saw a flamingo on the great pond,’ I would believe them. They saw a flamingo.”

There were four such people. He won’t name them, but said he had spoken personally with them. Grilled them.

What’s more, they all made their sightings in the same area.

“They have all come from an area that a coyote would include in its home range. I haven’t had a reliable report from Gay Head or Edgartown. They have come from the whole north shore area. Tea Lane, Meeting House Road, Indian Hill, that area.”

And it was a number of concerned landowners in that same area — Mr. Ben David declined to name them, either — who contacted him a couple of months back, asking about the prospect of the DNA testing.

He did not know the answer to their question, but he knew where to refer them, and eventually it was done.

Now, having seen the results, even spoken to the PhD who did the testing, he is convinced, although the scientist in him cautions that this is still a circumstantial case.

“If you ask me ‘Can you prove there is one coyote or more on the Island?’ I would have to say ‘No.’

“But given the DNA evidence and the integrity of the observers, if you asked ‘Do you believe there’s a coyote on the Island?’ I would say yes. In my heart, I do believe there’s a coyote on Martha’s Vineyard.”

Which raises two questions. How did it get here? And what are the ramifications of its being here?

Well, it could have come two ways. Either it swam or someone brought it.

The second possible explanation is not as ridiculous as it seems. In the past, people brought raccoons, skunks and chipmunks here. And possibly foxes.

But more likely it was washed up here.

Coyotes are good swimmers. And there is an established population on the Elizabeth Islands. Mr. Ben David points to a skull on the table beside him, of the only coyote previously found here. It washed up, dead, eight or 10 years ago.

“It was found on the north shore,” he said. “Most likely washed over from the Elizabeth Islands.”

As to the consequences, that depends on whether there is just one, or more.

Just one washashore would likely live out its existence without causing any trouble to anyone.

“It has an unlimited range of high quality habitat. The Vineyard has such a plethora of natural prey that the chances of it bothering livestock or pets are fairly minimal,” he said.

But a breeding colony would be a different matter. They can quickly multiply to astonishingly dense population levels.

“The potential — as we’ve seen by what has happened on Cape Cod — is serious,” he said.

“They do prey on cats and small dogs. There have literally been some horror show reports from Cape Cod. And if you had an established population, it could be a potential disaster for sheep farmers.”

The coyote was not native to this part of the world. They were creatures of the western United States until relatively recently. They only appeared in Massachusetts in about the past 50 years. But they now are established everywhere in the state except Martha’s Vineyard and Nantucket.

“So,” he said, “here on the Vineyard it would be the equivalent of an invasive species.

“They have a very wide diet. Small mammals like meadow voles, shrews. Reptiles, frogs, berries. There’s not much this animal won’t eat. It’s a formidable predator.

“Think of the wildlife management ramifications. We have so many creatures that are rare or endangered. Piping plovers, for instance.

“Wherever coyotes get established, it becomes almost impossible to free range sheep. Sheep are very vulnerable. And you wouldn’t want to let your little chihuahua run free.”